Butterfly valve seat

ABSTRACT

A seat structure for butterfly valves in which shim means are inserted between two body rings to adjustably compress a resilient seat axially to thereby effect the desired radial clearance between the internal diameter of the seat and the disc closure member.

United States Patent [72] inventor Hubert L. William [56] ReferencesCited Hinsdale, 1]]. UNITED STATES PATENTS 1 1 pp 40-241 2,564,0258/1951 Morton 277/188 1 Filed 2,739,855 3/1956 Bruning..... 277/188 [4511971 2,882,010 4/1959 Bryant 251/306 8 2,933,320 6/1961 146m 251/306 x 83,325,142 6/1967 Thompson. 251/306 3,393,697 7/1968 Fawkes 251/307 X[54] BUTTERFLY VALVE SEAT Primary Examiner-Henry T. Klinksiek 5 Claims,8 Brawl!!! 8 Anomey-George S. Schwind [52] US. Cl 251/307,

277/188 ABSTRACT: A seat structure for butterfly valves in which [51]Int. Cl. ..F16l1 1/226, shim means are inserted between two body ringsto adjustably F15j 15/16 compress a resilient seat axially to therebyefl'ect the desired [50] Field of Search 251/306, radial clearancebetween the internal diameter of the seat and 307, 170, 171, 172, 173;277/188 the disc closure member.

Patented Dec. 28, 1971 2 Sheets-Sheet 1 FIG. 3

BUTTERFLY VALVE SEAT BACKGROUND AND SUMMARY OF THE INVENTION Thisinvention relates to butterfly valves and in particular to a novel meansfor adjusting the clearance between the peripheral edge of the valvedisc and the internal diameter portion of the valve seat. The use ofbutterfly valves in installations necessitating valves having a diameterof several feet directs the requirement for construction of a valvewhich has an accessible adjusting means and also one which is simple andeconomical to fabricate and maintain. ln installations such as watermains the valve seats are usually of the moldedin-body type or extrudedrubber cut to length. Because of the size of such extrusion it isreadily apparent that variations will occur in tolerance of the seat sothat final installation of the valve will not be one which will form atight fit between the periphery of the valve disc and the seat. It istherefore necessary to make such adjustments at a close tolerance sothat the leakage across the valve will be kept to minimum both atassembly and after extensive use of the valve.

Numerous ways have been devised to accomplish an acceptable adjustingmeans for larger type butterfly valves such as grinding or finishing theperiphery disc member, and, radially adjustable-clamping means whichradially vary the inner diameter of the valve seat.

Recent developments in this particular art disclose the use ofcircumferential, segmental body rings which are inserted in an internalcircumferential recess in the valve body. A flexible seat element isalso placed within the recess aside of the rings. By separating therings, with usually some form of screw arrangement, the portion of theseat which is not confined within the recess is compressed so that itexpands to contact the outer periphery of the disc closure member sincethe internal diameter of the seat is reduced by separating the bodyrings. Conversely, if it is desired to increase the clearance betweenthe seat and disc, the body rings are moved toward each other.

It has been found that such arrangements have an undesirable effectsince they are utilizing a form of screw means to effect the separationof thetwo body rings. Adjustment of the valve seat by such screw meansis further undesirable since there is no positive assurance that theseat will remain in such a position subsequent to adjustment.Vibrations, impacts, the flow of fluids through the valve, etc. all tendto loosen such screw settings to thereby disturb the seat tolerance,even if a locking arrangement is used. In addition, the rusting andfusing of such screw means makes subsequent adjustments extremelydifiicult.

Screw adjusting means are also subject to electrolysis because of themany sharp edges and comers. It also leaves voids which are difficult tocoat to thereby prevent electrolysis and corrosion. The shim meansdisclosed herein a substantially reduces such raids to present a smoothsurface that is easily coated and readily protected from suchelectrolysis and corrosion.

Accordingly, it is the prime object of this invention to provide anadjusting means for such a body ring and seat arrangement which is ofpositive adjustment that will not deviate from the original setting andone which is not susceptible to disturbance caused by vibration, impactand the like.

A still further object is to provide a valve seat structure which may beadjusted in any desired arcuate location without disturbing theadjustment of other portions of the seat.

A yet further object is to provide a novel adjusting means which isreadily calculable since the clearance necessitated in a particulararcuate region may be assumed by the particular shim thickness.

Another object is to provide an improved seat structure whereby the seatclearance may be adjusted without removing either the seat or disc.

The present invention has a novel construction whereby the internaldiameter of the flexible seat of a butterfly valve, which is inproximity to the valve disc, may be adjusted at any circumferentiallocation. Such adjustment is accomplished by inserting or removingnovel, self-locking shims between body rings, which are positioned in acircumferential recess adjacent the seat, to decrease or increase thevalve disc clearance, respectively, depending upon the adjustmentdesired. At any circumferential location, the body rings may beseparated by a novel slot arrangement which permits the insertion of ascrewdriver between the two body rings adjacent the seat in the arcuateportion where adjustment is desired. Upon insertion of the screwdriverin its receptive slot, a pressing action separates the two rings toenable the insertion or removal of shims in order to procure the desiredseat-disc clearance. Such novel arrangement is inexpensive and may beperformed on the valve without removing the disc, seat or associatedparts. Also, such adjusting structure enables close tolerances to bemaintained without the use of any screws which may become separate fromthe rings by vibration, or shock, and enter the stream of fluid passingthrough the valve. Additionally, the shims have a novel offset portionwhich prevent them from falling instream since they are self-locking andare wedged between the two rings by the forces of the elastomer orflexible seat element which constantly exerts a force to maintain theshims in place.

Other objects and advantages of the instant invention will be apparentfrom the following description of the preferred embodiment hereindescribed and illustrated in the accompanying drawings.

IN THE DRAWINGS FIG. 1 is an end view of an assembly of a butterflyvalve embodying this invention;

FIG. 2 is a transverse sectional view taken at the centerline of theconstruction shown in FIG. 1;

FIG. 3 is a magnified, fragmentary sectional assembly view of the novelconstruction;

FIG. 4 is an end view of one segment of the locking ring;

FIG. 5 is a side view of one of the shims;

FIG. 6 is an end view of one segment of the compression ring;

FIG. 7 is a partial isometric of one segment of the locking ring; and,

FIG. 8 is a partial isometric of one segment of the compression ring.

With reference to the drawings, and in particular FIGS. 1 and 2, anexemplary butterfly valve body of the wafer type, generally indicated byreference numeral 1, is adapted to receive a disc or closure member 3which is secured to stem 5 by threaded tapered pins 7 and securing nuts8, or other conventional means. The stem 5 is journaled for rotation inthe body 1 by conventional bearings 9 and 11, which may also incorporatesealing means (not shown) in the usual manner. The disc 3 is rotatablebetween the closed position, wherein the peripheral portion 4 of thedisc is in circumferential contact with the flexible seat 12 to effectsealing, as shown in FIGS. 2 and 3, to an open position by rotating thestem in the conventional manner. In the latter position, no sealingfunction is performed between the seat and disc. The wafer body I hasbolt holes 2 equispaced about its outer periphery adapted to receivebolts passed through the body to adjacent pipe flanges (not shown) whichare positioned on both sides of the body to thereby secure the bodybetween the flanges in a conventional manner.

The above reference to a cast wafer-type body, which incorporates thenovel seat adjusting means hereinafter disclosed, is only exemplary ofthe numerous types of valve bodies, disc and stem arrangements which maybe either cast or fabricated and utilized with the instant invention.

The instant invention is directed to an improved means for effecting theclearance between the periphery 4 of the disc 3 and the flexible seat 12which is inserted in a circumferential radial groove or recess 15 whichis formed of opposing sides l7, l9 and bottom portion 21, as shown inFIG. 3. The recess extends around the entire periphery of the valve andis so positioned as to be normal to the central axis of the valve and inproximity to the disc 3 when the latter is in a closed position, as inFIG. 2.

The recess contains a flexible valve seat 12 of generally T-configuration wherein the leg of the T projects beyond the interior ofthe valve to permit the disc periphery 4 to contact the seat withoutinterference from the interior of the body 1. The seat 12 is continuousand may be of any elastomer or fluorocarbon capable of flexibledistortion and may be constructed of other geometrical cross-sectionalconfigurations if so desired. The seat 12 lies in the bottom of recess15 whereby one of its sides is positioned against side 19 of the saidrecess to form complementary mating surfaces, as shown in FIG. 3.

The adjusting means 23 for effecting the adjustment between the seat 12and disc periphery 4 includes a segmented compression ring 25 which isplaced in recess 15 between sides 17 and seat 12. The segmental portionsof the ring 25, as shown in FIGS. 6 and 8, are placed in end-to-endrelationship around the entire periphery of the said recess so that theseat 12 may be acted on by the ring 25 along the entire circumferentialsurface to be hereinafter explained.

Positioned between the segmental compression ring 25 and side 17 ofrecess 15 is a segmental locking ring 27 which overlays an offsetportion 26 of the compression ring 25. This locking ring 27, as clearlyshown in FIGS. 4 and 7, has a tapered projection 29 extending from theside which is in proximity to side 17 of recess 15. Projection 29 isadapted to snap into a circumferential axial groove 31 which extendsaround the entire periphery of side 17 of recesses 15, similar to theseat 12, compression ring 25 and locking ring 27. All of these recitedelements are thus positioned in recess 15 around the entire innercircumference of the valve body and cooperate to adjust the valve seat.

Positioned between the compression ring 25 and the locking ring 27 areshim means 33, as shown in FIGS. 3 and 5, which are adapted to beinserted or removed between rings 25 and 27 at any circumferentiallocation to thereby permit adjustment between the outer periphery 4 ofthe disc 3 and seat 12.

With reference to FIG. 3, it is apparent that the compressing ring 25may be moved axially toward the seat 12 by the addition of shim means 33inserted between the ring 25 and locking ring 27 since the seat 12 willcompress. Upon the insertion of such shim means 33, the ring 25 will bemoved axially to thereby squeeze the seat so that the free portion 13,which is not confined and is in proximity to the disc 3, is extruded tothereby decrease the distance between the said seat and disc. Since theseat is confined'except for the portion 13, any movement of thecompression ring toward the seat will decrease the inner diameter of theseat to thereby decrease the clearance or fit between the disc.Conversely, the removal of shim means 33 between rings 25 and 27 willpermit the seat to expand toward the compression ring and relax itsconfined position thereby increasing the diameter of the seat and theclearance between the disc 3 and adjacent seat portion 13.

With reference to FIGS. 4 and 7, the insertion of shim means isaccomplished by placing a screwdriver or similar tool into slot means 35which are radially positioned at substantially equal intervals aroundthe periphery of the ring 27. By inserting a screwdriver into a slot 35adjacent a seat area to be adjusted, a leverage may be exerted thereonto separate the rings by compressing the seat an amount sufficient topermit the insertion of the desired thickness shim means between the twosaid rings. Upon removal of the screwdriver, the elastomer seat willforce the rings into position whereby the shim means will have decreasedthe confined volume of the seat 12 to thereby squeeze a portion of theseat into contact with disc 3. To prevent the shims from falling intothe flow of fluid passing through the valve each shim means 33 includesa shank portion 34 and an projection 39, as shown in FIG. 5.

To remove the seat, as for repair or replacement purposes, an additionalset of slots 37 are positioned on the side of the locking ring which hasthe projection 29 thereon. Thus, to initiate removal of the novelseat-ad usting means, a screwdriver is inserted in the slot 37 which isadjacent the sidewall, 17 of recess 15. The locking ring is thenseparated from the wall by exerting a force on the screwdriver so thatthe seat is axially compressed a distance sufficient enough to allowclearance of the projection 29 to be released from recess 31. Projection39 of shim 33 is adapted to be received by a circumferential channel 41of ring 25 which is in proximity to the projection 39 of ring 25, noteFIG. 3. Thus, once the shim means 33 is inserted between the two rings,the projection 39, which comprises a locking means, will prevent thesaid shim from being dislodged since in order to remove the shim it isnecessary to separate the rings 25 and 27 a distance greater than thethickness of the shims offset portion.

Thus, the novel locking arrangement between the locking ring 27 and body1, along with the novel locking means 39 of shim means 33, and, thecooperation of these elements with the offset portion 26 of compressionring 25 provide a unique adjusting structure for a butterfly valve seat.Such adjusting means not being susceptible to impact, vibration andundesirable changes in seat-disc clearance.

Iclaim:

1. A butterfly valve comprising:

a. a cylindrical valve body, said body having a continuous interiorcircumferential recess with opposing sidewalls;

b. a resilient valve seat positioned in said recess adjacent one saidwall;

c. a valve disc rotatively mounted in said body in proximity to saidseat;

(1. a pressure ring positioned in said recess adjacent said valve seatand adapted to compress said valve seat, said pressure ring having anoffset portion whereby said pressure ring and said one wall overlieportions of said valve seat to prevent said seat from being dislodgedfrom said body recess;

e. a locking ring positioned in said recess between the other saidsidewall and said pressure ring and overlying said offset portion ofsaid pressure ring;

f. shim means selectively positioned between said pressure ring and saidlocking ring, said shim means adapted to displace said compression ringtoward said seat to thereby squeeze said seat out of said recess intocontact with said disc.

2. A valve as claimed in claim 1 wherein said offset portion has acircumferential channel in proximity thereto and wherein said shim meansincludes locking means comprising a projection on one end thereofadapted to be received by the circumferential recess in said pressurering to thereby prevent said shims from being accidentally dislodged.

3. A valve as claimed in claim 2 wherein said sidewall adjacent saidlocking ring includes a circumferential groove, and, said locking ringincludes a cam portion adapted to project into said groove to therebyprevent said rings from being dislodged.

4. A valve as claimed in claim 3 wherein said locking n'ng furtherincludes slot means positioned on opposite sides thereof, said slotmeans adapted to receive a screwdriver to selectively separate saidlocking ring from said pressure ring.

5. A valve as claimed in claim 1 wherein said locking and pressure ringsare segmental.

1. A butterfly valve comprising: a. a cylindrical valve body, said bodyhaving a continuous interior circumferential recess with opposingsidewalls; b. a resilient valve seat positioned in said recess adjacentone said wall; c. a valve disc rotatively mounted in said body inproximity to said seat; d. a pressure ring positioned in said recessadjacent said valve seat and adapted to compress said valve seat, saidpressure ring having an offset portion whereby said pressure ring andsaid one wall overlie portions of said valve seat to prevent said seatfrom being dislodged from said body recess; e. a locking ring positionedin said recess between the other said sidewall and said pressure ringand overlying said offset portion of said pressure ring; f. shim meansselectively positioned between said pressure ring and said locking ring,said shim means adapted to displace said compression ring toward saidseat to thereby squeeze said seat out of said recess into contact withsaid disc.
 2. A valve as claimed in claim 1 wherein said offset portionhas a circumferential channel in proximity thereto and wherein said shimmeans includes locking means comprising a projection on one end thereofadapted to be received by the circumferential recess in said pressurering to thereby prevent said shims from being accidentally dislodged. 3.A valve as claimed in claim 2 wherein said sidewall adjacent saidlocking ring includes a circumferential groove, and, said locking ringincludes a cam portion adapted to project into said groove to therebyprevent said rings from being dislodged.
 4. A valve as claimed in claim3 wherein said locking ring further includes slot means positioned onopposite sides thereof, said slot means adapted to receive a screwdriverto selectively separate said locking ring from said pressure ring.
 5. Avalve as claimed in claim 1 wherein said locking and pressure rings aresegmental.